The purpose of the Radiation Therapy Oncology Group is to form a cooperative group of Radiation Therapy Research and Clinical Centers for conducting joint clinical investigations. The group will conduct clinical trials and other cooperative clinical studies in an endeavor to advance knowledge in the curative and palliative treatment of cancer. Through the collaboration of the Radiation Therapy Oncology Group an adequate number of patients will be provided to answer significant questions in the treatment of cancer not possible on the basis of the number of patients seen in any one institution. An integral part of the Radiation Therapy Oncology Group is a sophisticated biostatistical center which will ensure the development of satisfactory methodology for the studies, and will aid in establishing an order of priorities for those studies which are of the greatest, immediate importance and which can yield an answer in a reasonable period of time. The RTOG will make possible the collection of long-term data with regard to radiation complications and patient survival, will integrate study programs in cancer with those in other disciplines, and will enrich training programs in oncology and radiadion therapy. During the past 30 months, the University of Pennsylvania has contributed a significant number of patients to the current RTOG studies, and as a member of the RTOG, is requesting continued funds to support its further participation in these cooperative clinical trials.